On Sunday 10 April 2011 10:55:25 you wrote:
> as I wrote yesterday when I started this thread, there is only kdm-trinity
> installed.

then you have evtl. missed to also install kcontrol-trinity (which will allow 
you configure kdm from kontrolcenter)

> Is there a way to test kdm? sudo kdm �doesn't do anything.

that's clear, as it is probably already running :)
try 
sudo killall X
then from text-console, sudo /opt/trinity/bin/kdm.

werner